A French tourist has been kidnapped in Algeria by a militant group linked to Islamic State (IS), French Foreign Minister Laurent Fabius has confirmed.

Herve Gourdel, 55, was seized on Sunday in the unsettled north-east Kabylie area.

Algerian militant group Jund al-Khilafa threatened to kill him if France did not halt air strikes on Iraq.

Mr Fabius said an online video that showed Mr Gourdel flanked by armed men was authentic.

He said France would do everything it could to liberate Mr Gourdel, but that the situation was "extremely critical."

Islamic State militants warned on Sunday they would target Americans and other Western citizens, "especially the spiteful and filthy French", after French jets joined the US in carrying out strikes in Iraq on IS targets.

Media captionLaurent Fabius: "The situation is extremely critical"

France on Monday raised the threat level for 30 of its embassies throughout the Middle East and Africa in response to what Interior Minister Bernard Cazeneuve called "yet another demonstration of the barbarism of these terrorists".

IS jihadists have seized large swathes of territory in eastern Syria and across northern and western Iraq, forcing tens of thousands of people to flee their homes this year.

French Prime Minister Manuel Valls said there would be "no discussion, no negotiation" with the kidnappers. "If you give in, if you go back one inch... you give [terrorism] this victory," he told French radio while on a visit to Germany on Tuesday.

Image copyrightReutersImage caption
In this still from the video, Herve Gourdel can be seen with his captors

Who are Jund al-Khilafa?

Previously part of al-Qaeda in the Islamic Maghreb (AQIM), which grew out of Algerian Islamist groups involved in 1990s civil war

Many residents fled the region's forests and mountains in recent years due to insecurity

Group said to be led by Abdelmalek Gouri, known as Khaled Abou Slimane, 37

14 September, pledged allegiance to Islamic State

Image copyrightAPImage caption
The Kabylie region is a rugged and mountainous area of Algeria

'Extreme cruelty'

France's foreign ministry said in a statement: "We confirm the authenticity of the video showing images of French hostage Herve Gourdel, kidnapped in Algeria in the region of Tizi Ozou on Sunday."

"The threats made by this terrorist group show once again the extreme cruelty of [Islamic State] and those who say they are affiliated to it."

Speaking in New York, where he is attending the UN General Assembly, Mr Fabius told reporters: "We will do everything we can to liberate hostages... but a terrorist group cannot change France's position."

In the video, Mr Gourdel, flanked by two masked men, identifies himself as a 55-year-old from Nice, southern France.

Apparently speaking under duress, he said: "This armed group is asking me to ask you [French President Francois Hollande] to not intervene in Iraq."

French media say he is an experienced mountain guide and photographer with a taste for exploring, who set up a hiking centre in the Mercantour national park north of Nice.

The Algerian interior ministry said he and two Algerian companions had been driving through mountains near the village of Ait Ouabane, when they were stopped by armed men.